// Copyright (c) 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "content/common/external_ipc_dumper.h"
#include "base/files/file_path.h"
#include "base/logging.h"
#include "base/native_library.h"
#include "base/path_service.h"
#include "build/build_config.h"

namespace {

typedef IPC::ChannelProxy::OutgoingMessageFilter* (*GetFilterFunction)();
typedef void (*SetDumpDirectoryFunction)(const base::FilePath&);

const char kFilterEntryName[] = "GetFilter";
const char kSetDumpDirectoryEntryName[] = "SetDumpDirectory";

#if defined(OS_WIN)
#define IPC_MESSAGE_DUMP_MODULE FILE_PATH_LITERAL("ipc_message_dump.dll")
#else
#define IPC_MESSAGE_DUMP_MODULE FILE_PATH_LITERAL("libipc_message_dump.so")
#endif

} // namespace

namespace content {

IPC::ChannelProxy::OutgoingMessageFilter* LoadExternalIPCDumper(
    const base::FilePath& dump_directory)
{
    base::FilePath module_path;
    if (!PathService::Get(base::DIR_MODULE, &module_path)) {
        LOG(ERROR) << "Unable to get message dump module directory.";
        return NULL;
    }

    base::FilePath library_path = module_path.Append(IPC_MESSAGE_DUMP_MODULE);
    base::NativeLibraryLoadError load_error;
    base::NativeLibrary library = base::LoadNativeLibrary(library_path, &load_error);

    if (!library) {
        LOG(ERROR) << load_error.ToString();
        return NULL;
    }

    SetDumpDirectoryFunction set_directory_entry_point = reinterpret_cast<SetDumpDirectoryFunction>(
        base::GetFunctionPointerFromNativeLibrary(
            library, kSetDumpDirectoryEntryName));
    if (!set_directory_entry_point) {
        LOG(ERROR) << kSetDumpDirectoryEntryName
                   << " not exported by message dump module.";
        return NULL;
    }
    set_directory_entry_point(dump_directory);

    GetFilterFunction filter_entry_point = reinterpret_cast<GetFilterFunction>(
        base::GetFunctionPointerFromNativeLibrary(library, kFilterEntryName));
    if (!filter_entry_point) {
        LOG(ERROR) << kFilterEntryName << " not exported by message dump module.";
        return NULL;
    }

    return filter_entry_point();
}

} // namespace content
